So, I just lost 14 platys in two days. It started with all the fish swimming right at the surface of the water, then all of a sudden they started dying! When they were hanging at the surface I did a level check with my API master test kit and they were:
Ammonia 0
Nitrite 0
Nitrate 40.
Ph 7.4
Clear water
So..... I did a 30% water change to get the nitrate out. I used API stress coat and API stress zyme and API aquarium salt in the new water that was the same 76 degrees that my tank lives at.
The next thing I know one by one about an hour apart they all died. Nitrate dropped to 30 and ammonia and nitrite were still zero.
I looked carefully at the dead fish and there is no fuzz, white flecks, redness, scales sticking out, or anything wierd.
I feed them 3 tetra tropical crisps per fish twice a day, and everything was hunky dory until all of a sudden they started acting funny and dying.
The only fish that survived was a baby green Cory catfish.
I have 3 bubblers, 2 live plants, and a waterfall filter, so oxygen should not be a problem.

Huh. I'm at a loss. Can I see some pictures of your tank? Maybe there's something you look at every day and think of as normal that would immediately pop out to someone else's eyes.


"What's that?" "Oh, that's just my crayfish. But seriously, why are my neon tetras disappearing? I've searched inside and around the tank and I can't find them."
Something like that.